Method and Apparatus for Forwarding Traffic of Switching System

1. A method for forwarding traffic of a switching system, wherein the switching system comprises a first line card chassis (LCC) at least one second LCC, and at least one third LCC; wherein the first LCC, the at least one second LCC, and the at least one third LCC are interconnected according to a wireless mesh form topology; and the method comprises: receiving, by the first LCC, a packet comprising first and second sub-packets to be distributed to first and second links, and parsing the packet to acquire a destination address of the packet; and when the destination address indicates that the packet is to be sent to the third LCC and when a currently preset configuration mode of the switching system is a first configuration mode, bearing, by the first LCC, the packet on the first and second links, and forwarding the packet to the third LCC, including preferentially distributing, by the first LCC, the packet to at least one link in the first link, and distributing a remaining packet in the packet to at least one link in the second link after the at least one link in the first link reaches a saturation state, wherein the first link is a directly connected two-hop link between the first LCC and the third LCC, and a quantity of links comprised by the first link is at least one, the second link is an n-hop link that passes through the at least one second LCC and that is between the first LCC and the third LCC, and a quantity of links comprised by the second link is at least one, wherein n is a natural number, 3≦n≦N, and N is a natural number greater than or equal to 3; and the first configuration mode indicates that an N-hop mode is currently applied to the switching system; and separately adding, by the first LCC, a first original time-scale to the first sub-packet, and adding a second original time-scale to the second sub-packet, wherein the first original time-scale indicates an initial time at which the first sub-packet arrives at the first LCC, and the second original time-scale indicates an initial time at which the second sub-packet arrives at the first LCC, enabling the third LCC to separately obtain, according to a first forwarding delay of the first sub-packet and a second forwarding delay of the second sub-packet, a first time-scale by adding a first time-scale compensation to the first original time-scale and a second time-scale by adding a second time-scale compensation to the second original time-scale, enabling a time sequence of the first and second time-scales to be consistent with a time sequence of the first and second original time-scales, wherein a sum of the first forwarding delay and the first time-scale compensation equals a sum of the second forwarding delay and the second time-scale compensation.

2. The method according to claim 1 , wherein the method further comprises: when the destination address indicates that the packet is to be sent to the third LCC and when the currently preset configuration mode of the switching system is a second configuration mode, bearing, by the first LCC, the packet on the first link, and forwarding the packet to the third LCC, wherein the second configuration mode indicates that a two-hop mode is currently applied to the switching system.

3. The method according to claim 2 , wherein the bearing, by the first LCC, the packet on the first link, and forwarding the packet to the third LCC comprises: evenly distributing, by the first LCC, the packet to the at least one link in the first link in a round-robin manner, to perform the forwarding the packet to the third LCC.

4. The method according to claim 2 , the bearing, by the first LCC, the packet on the first link, and forwarding the packet to the third LCC comprises: acquiring, by the first LCC, status information of the at least one link in the first link; and distributing, by the first LCC according to the status information of the at least one link in the first link, the packet to the at least one link in the first link to perform the forwarding the packet to the third LCC.

5. The method according to claim 4 , wherein when the status information of the at least one link in the first link indicates congestion degrees of the at least one link in the first link, the distributing, by the first LCC according to the status information of the at least one link in the first link, the packet to the at least one link in the first link to perform forwarding comprises: adjusting, by the first LCC according to the congestion degrees of the at least one link in the first link, traffic of the packet distributed to the at least one link in the first link, to enable traffic borne on each link in the first link to match a congestion degree of the link.

6. The method according to claim 4 , wherein when the status information by the first LCC according to the status information indicates abnormality information of the at least one link in the first link, the distributing, by the first LCC according to the status information by the first LCC according to the status information, the packet to the at least one link in the first link to perform forwarding comprises: determining, by the first LCC, an abnormal link in the first link according to the abnormality information of the at least one link in the first link; and distributing, by the first LCC, the packet to a normal link in the first link to perform the forwarding.

7. The method according to claim 1 , wherein the bearing, by the first LCC, the packet on the first and second links, and forwarding the packet to the third LCC comprises evenly distributing, by the first LCC, the packet to the at least one link in the first and second links in a round-robin manner, to perform forwarding.

8. The method according to claim 1 , wherein the bearing, by the first LCC, the packet on the first and second links, and forwarding the packet to the third LCC comprises: acquiring, by the first LCC, status information of the at least one link in the first and second links; and distributing, by the first LCC according to the status information of the at least one link in the first and second links, the packet to the at least one link in the first and second links to perform forwarding.

9. The method according to claim 8 , wherein when the status information of the at least one link in the first and second links indicates congestion degrees of the at least one link in the first and second links, the distributing, by the first LCC according to the status information of the at least one link in the first and second links, the packet to the at least one link in the first and second links to perform forwarding comprises: adjusting, by the first LCC according to the congestion degrees of the at least one link in the first and second links, traffic of the packet distributed to the at least one link in the first and second links, to enable traffic borne on each link in the first and second links to match a congestion degree of the link.

10. The method according to claim 8 , wherein when the status information of the at least quantity of links comprised by the first and second links indicates abnormality information of the at least one link in the first and second links, the distributing, by the first LCC according to the status information of the at least one link in the first and second links, the packet to the at least one link in the first and second links to perform forwarding comprises: determining, by the first LCC, an abnormal link in the first and second links according to the abnormality information of the at least one link in the first and second links; and distributing, by the first LCC, the packet to a normal link in the first and second links to perform the forwarding.

11. The method according to claim 1 , wherein the first LCC forwards the packet to a destination fabric interface chip (FIC) in the first LCC when the destination address indicates that the packet is to be sent to the first LCC.

12. A first line card chassis (LCC) in a switching system comprising a first LCC, at least one second LCC, and at least one third LCC, wherein the first LCC is interconnected with the at least one second LCC and the at least one third LCC according to a wireless mesh form topology; and the first LCC comprises at least one switch element (SE), wherein the at least one SE comprises: a first acquiring module, configured to receive a packet comprising first and second sub-packets to be distributed to first and second links, and parse the packet to acquire a destination address of the packet; and a sending module, configured to, when the destination address indicates that the packet is to be sent to the third LCC, and when a currently preset configuration mode of the switching system is a first configuration mode, bear the packet on first and second links, and forward the packet to the third LCC, including preferentially distributing, by the first LCC, the packet to at least one link in the first link, and distributing a remaining packet in the packet to at least one link in the second link after the at least one link in the first link reaches a saturation state; wherein the first link is a directly connected two-hop link between the first LCC and the third LCC, and a quantity of links comprised by the first link is at least one; the second link is an n-hop link that passes through the at least one second LCC and that is between the first LCC and the third LCC, and a quantity of links comprised by the second link is at least one, wherein n is a natural number, 3≦n≦N, and N is a natural number greater than or equal to 3; and the first configuration mode indicates that an N-hop mode is currently applied to the switching system; and a second time-scale adding module, configured to separately add first and second original time-scales to the first and second sub-packets, respectively, wherein the first and second original time-scales indicate initial times at which the first and second sub-packets, respectively, arrive at the first LCC, enabling the third LCC to separately obtain, according to a first forwarding delay of the first sub-packet and a second forwarding delay of the second sub-packet, a first time-scale by adding a first time-scale compensation to the first original time-scale and a second time-scale by adding a second time-scale compensation to the second original time-scale, enabling a time sequence of the first and second time-scales to be consistent with a time sequence of the first and second original time-scales, wherein a sum of the first forwarding delay and the first time-scale compensation equals a sum of the second forwarding delay and the second time-scale compensation.

13. The first LCC according to claim 12 , wherein the sending module is further configured to: when the destination address indicates that the packet is to be sent to the third LCC, and when the currently preset configuration mode of the switching system is a second configuration mode, bear the packet on the first link, and forward the packet to the third LCC, wherein the second configuration mode indicates that a two-hop mode is currently applied to the switching system.

14. The first LCC according to claim 13 , wherein the sending module is configured to evenly distribute the packet to the at least one link in the first link in a round-robin manner, to perform the forwarding the packet to the third LCC.

15. The first LCC according to claim 13 , wherein: the SE further comprises: a second acquiring module; the second acquiring module is configured to acquire status information of the at least one link in the first link; and the sending module is configured to distribute, according to the status information, acquired by the second acquiring module, of the at least one link in the first link, the packet to the at least one link in the first link to perform the forwarding the packet to the third LCC.

16. The first LCC according to claim 15 , wherein when the status information acquired by the second acquiring module indicates congestion degrees of the at least one link in the first link, the sending module is configured to adjust, according to the congestion degrees of the at least one link in the first link, traffic of the packet distributed to the at least one link in the first link, to enable traffic borne on each link in the first link to match a congestion degree of the link.

17. The first LCC according to claim 15 , wherein when the status information acquired by the second acquiring module indicates abnormality information of the at least one link in the first link, the SE further comprises a first determining module, wherein: the first determining module is configured to determine an abnormal link in the first link according to the abnormality information of the at least one link in the first link; and the sending module is configured to distribute the packet to a normal link in the first link to perform the forwarding.

18. The first LCC according to claim 12 , wherein the sending module is configured to evenly distribute the packet to the at least one link in the first and second links in a round-robin manner, to perform forwarding.

19. The first LCC according to claim 12 , wherein the SE further comprises a third acquiring module, wherein: the third acquiring module is configured to acquire status information of the at least one link in the first and second links; and the sending module is configured to distribute, according to the status information, the packet to the at least one link in the first and second links to perform forwarding.

20. The first LCC according to claim 19 , wherein when the status information acquired by the third acquiring module indicates congestion degrees of the at least one link in the first and second links, the sending module is configured to adjust, according to the congestion degrees of the at least one link in the first and second links, traffic of the packet distributed to the at least one link in the first and second links, to enable traffic borne on each link in the first and second links to match a congestion degree of the link.

21. The first LCC according to claim 19 , wherein when the status information acquired by the third acquiring module indicates abnormality information of the quantity of links comprised by the first and second links, the SE further comprises a second determining module, wherein: the second determining module is configured to determine an abnormal link in the first and second links according to the abnormality information of the at least one link in the first and second links; and the sending module is configured to distribute the packet to a normal link, in the first and second links to perform the forwarding.

22. The first LCC according to claim 12 , wherein the first LCC further comprises a fabric interface chip (FIC); and the sending module is further configured to forward the packet to the FIC when the destination address indicates that the packet is to be sent to the FIC.